Turret lathe



' R. M. GAMBLE TURRET LATHE ,July 31, 1951 Filed July 26, 1945 7 sheets-sheet 1 fg!! l R. M. GAMBLE TURRET LATHE July 31, 1951 Filed July 26, 1945 7 Sheets-Sheet 4 V -ZW Vf R. M. GAMBLE TURRET LATHE July 3l, 1951 '7 Sheets-Shea?I 5 Filed July 26, 1945 Nady July 31, 1951 R, M, GAMBLE 2,562,266

TURRET LATHE:

Filed July 2e, 1945 7 sheets-sheet 7 Patented July 31, 1951 UNITED sTATEs PATENT oFElcE TURRET LATHE Ralph M. Gamble, Springfield, Vt., assignor to Jones & Lamson Machine Company, Springfield, Vt., a corporation of Vermont Application July 26, 1945, Serial No. 607,159

(Cl. .Z9-42) 4 Claims.

This invention relates to turret lathes and ha for an object to provide a hydraulic system for actuating mechanical controls to provide an automatic cycle of operations. This takes advantage of all the desirable features of the mechanical controls, such, for example, as precision control and smoothness of feed, and yet provides for automatic cycle control. Thus the machine may be provided with a turret ram and a cross slide, both with mechanical actuating means, together with hydraulic controls for the actuating means by which the operations may be automatic, semiautomatic, or if desired with the hydraulic mechanism inoperative and the mechanical actuating means under manual control.

A further object of the invention is to provide for fluid pressure pulse operation of the controls rather than continuous pressure so that it is unnecessary to maintain high pressure conditions in the major portion of the hydraulic system, thus avoiding troublesome leakage problems. f

For a complete understanding of this invention, reference may be had to the accompanying drawings, in which n Figures 1 and 2y are front elevation and top plan views, respectively, of a turret lathe embodying the invention. n

Figure 3 is a fragmentary rear elevation of the machine to a larger scale than Figure 1.

Figures 4 and 5 are detail sectional views to a larger scale on lines 4--4 and 5 5, respectively, of Figure 1.

Figure 6 is a detail sectional View to a larger scale on line 6-6 of Figure 5.

Figure 7 is a detail sectional view on line 'I--l of Figure 6.

Figure 8 is a View partly in front elevation 'l and partly in section through the ram knock-off actuating means and to a larger scale than Figure 1.

Figure 9 is a view similar to a portion of Figplug in section.

Figures 10 and 11 are detail sectional views on lines Iii-I0 and II-I I, respectively, of Figure 8.

ure 8, but to larger scale and showing a threaded Figure 12 is a detail sectional view to a larger through the pilot and directional ram controll valves in forward position, the actuating mechanism being shown in elevation.

Figures 15, to 19, inclusive, are detail sectional views to a larger scale on the correspondingly numbered section lines of Figure 14.

V:ses

Figures 20 and 2l are views partly in elevation and partly in section of the pilot valve in neutral and in retire positions, respectively.

.Figure 22 is a diagram of the hydraulic connections.

As shown best in Figure 1, the machine comprises a bed I, supporting at one end in a headstock 2, a rotary headstock spindle 3 having a suitable work-holding chuck Il at its forward end. The bed I has ways 5 along which is slidable lengthwise of the spindle 3, a ram 6 on which the tool-holding turret I is supported for indexing motion about a vertical axis.

The machine is also provided with a cross carriage 8 mounted for forward and backward motion, and as shown in Figure 5, adapted to carry forward the rear tools 9 and IE), respectively, which may be brought into action, the forward tool by moving the carriage rearwardly from an intermediate idle position, and the rear tool by moving the carriage forwardly from this same position. Suitable mechanical drive means for feeding the ram toward the spindle and for moving the carriage 8, rst quickly from the intermediateidle position, and then slowly for feed of the tool against the work may be provided, these being driven from the rotary feed shaft II in the well knownmanner. VSuitable provision ismade for releasing the slow feed motionl of the ram when the tool carried by the turret then in operative relation to the work approaches the work axis to a predetermined point, and means is also provided for returning the carriage to mid position under fast speed. All this may be as disclosed in the Lovely Patent No. 2,006,144 granted June 25, 1935, for Feed Knock-Off Mechanism for Lathes. The feed knock-off mechanism for the ram includes the lever I2, and the feed knock-off mechanism for the carriage includes the lever I3, these corresponding to and being identical with the corresponding'parts shown in the Lovely patent.

The present invention provides, besides the mechanisms shown in this patent, hydraulic mechanism for producing a forward quick motion of the ram before the slow mechanical feed is thrown into action, and for retiring the ram in fast motion on termination of the slow feed. It also has hydraulic mechanism for throwing out the fast feed of the ram, and throwing in the slow forward feed, and for causing the knock-off of the ram feed to throw in the hydraulic fast retire mechanism. It also includes hydraulic mechanism for actuating the clutches for the mechanical carriage motion to change from fast to slow-feed,v and when the knock-off operates,

to throw in the fast motion to retire the carriage to central position.

The mechanism for controlling the ram, and also for initiating the hydraulic control of the cross carriage, includes a lay shaft I5 which is carried by the ram and is journaled for rotation and is connected to the turret so as to be indexed with the indexing of the turret. As shown herein, the turret I is provided with six faces, and likewise the lay shaft I5 is provided with a sixfaced bar I6 which is xed to turn therewith.

On each of these aces of the lay shaft l@ there may be secured in adjustable axial positions therealong, a dog holder i1 having four slots spaced laterally of each other and in any selected of which a dog I8 may be secured, the arrangement being such that each of the four dog positions on a carrier at one of the faces of the member i6 is alined with one of four hydraulic valves arranged in staggered relation in a stationary valve casing ie asshown best in Figure 10. The lay shaft l5 is indexed in time with the indexing of .the turret and for this purpose it is connected through a train of gears shown in Figure 2 and in dotted lines in Figure 4 at 2B, to a shaft 2l, which as shown in Figure 2, is connected to rotate with the turret l. Also rotatable with the rotatable shaft 2l is a series of adjustable stop screws 22 which may be set to impinge upon the knock-oil? actuating mechanism `for theturret ram motion to limit the forward stroke of the turret for each turret position independently of all the others. This .knock-od mechanism is fully shown and described in the Lovely Patent No. 2,066,144. hereinbefore mentioned. As is usual practice in connection with turret lathes, means are provided for indexing lthe turret by the retire motion of the .rarn'adjacent to its limit of such retire motion. Thisy means, for example, may be that shown in the Lovely and Cheever Patent No. 2,094,993, granted October 5, 1937, for Lathes. Hydraulic means are provided for producing a rapid motion of the ram betweenits retire position and the position where the tool is approaching` the work, and it is desirable that the slow feed begin. This means is shown best in Figure 3 and diagramma-tically in Figure 22. It comprises a pair of hydraulic cylinders 25 and 25 secured at opposite ends to the ram at the brackets 2l, 28 and 2%, the bracket 28 being common to both cylinders. Within the cylinders are the stationary piston rods 3U and 3i which communicate with the pipes 32 and 33. The piston rods are hollow, and have pistons (not shown) riding in the Yrespective cylinders. These. hydraulic 'cylinders are thus single acting cylinders, hydraulic pressure being `admitted to one and exhausted from the other alternately to move the ram in opposite directions.

All of the valves in the casing i9 and actuated by any of the dogs i3 on the lay shaft are alike, and similar valves in a casing 34 are also employed in connection with the control of the carriage motions, as will later appear. One ofthese valves is shown in section in Figure 11. ItY comprises a valve plunger having a stem projecting through a slot in the valve cover plate fil. There are four of these valves which may be actuated at suitable times by dogs i8 on the lay shaft, and the stems for these valves are marked, respectively, A, B, C and D. The plunger 4i] of each valve has a neck portion @2 intermediate its ends' and is normally pressed upward by aspring 4-3 reacting between its base and a closure plug fifi in the bottom 'of the valve casing. Fluid under pressure is admitted through the pipe 45 and passage 4B, but when the valve stem 4i) is lifted, it cannot pass further. On depression of the valve 40, however, communication is made around the neck 42 of the valve through the passage 4'! into a connecting pipe. As soon as the valve is allowed to rise again, pressure in the passage 4l is vented out through the passages 49 and 50 to the drain 5i, this drain also leading through the passage 52 beneath the valve lli?. Similarly the cross slide 8 is provided with dog carriers 6G, each having four places for the selective attachment of dogs tlA across its width, and which can impinge upon the hydraulic valves having the stems E, F, G and H.

Beside these dog controlled Valves, there is provided a directional control Valve 1G, shown in detail in Figures 14 to 21, a pilot valve 'H (shown in detail in Figure 14), a feed shifter unit valve i2 (shown in Figure 13), a fast motion hydraulic actuator 13 (shown in detail in Figure l2), and two identical knock-off actuated valves 14a and 74h, the Valve 74a being actuated bythe ram knock-oil, and the ram 'Mb by the carriage knock-ofi.

Ram control mechanism and cycle Hydraulic pressure is derived from a suitable source (not shown) which feeds through the pipe Si) (see Figure 22). This pressure leads from the pipe 88 through the pipe iii to thedirectional control valve. Assuming that the lathe is tooled and ready to operate and with the ram at rest just after indexing in a position to advance in fast motion, the lever being in central neutral position, shown in Figure 20, the operatorl shifts the lever 85 of the pilot valve 'El to advance position shown in full lines in Figure lli. rhis also moves the directional control valve 'l into the position shown, this valve being cou-pled to the pilot valve. In this position of the parts communication is opened from the pressure pipe Si around the neck 81 of the directional control valve to the pipe -33 leadingY into the fast motion ram advance cylinder 25. At the same time, the fast motion retire cylinder 26 is discharged through the pipe32 past the directional valve shoulder 38, through the valve passage 69 to the drain pipe 9i);Y This causes the ram to advance in fast motion. A spring detent Si engagingin an annular recess 92 of the directional control valve "it retains the feed lever B5 andthe pilot and directional control valves 'H and i9 in this position.

As the tool on the turret then in operative position comes near to the work, a dog i8 on'the lay shaft engages and depresses the Valve stem A. Pressure from the pipe 8@ reaches the valve casing containing the stems A, B, C and D through a pipe 9E, check valve 9b, and pipe d5'. Depression of the stem A opens communication from this pressure pipe to the pipe 9i, which connects with the passage 4l of this valve, and .to the casing of the pilot valve H where it passes through the valve passages e8 Y(see `Figure 19) out through the pipe 99, to the ram feed lever 'Mia where it enters at itil. It also passes through the passage lill of the pilot valve casing past the ball check valve 02 (see Figure l5) and into the central bore of the valve casing between the closure plug H33 and the sleeve piston HM. Pressure on the left hand end of the sleeve piston |84 pushes the pilot valve to the mid or neutral position shown in Figure 2G, and moves the directional'control valve to its central position which shuts oib'oth pipes 3 2 and 33 leading to the ram cylinders and connects lboth fast motion cylinders to the passagek and the drain 90. This cuts out the high speedhydraulic feed. The pressure reaching the valve 14a, lifts the ram knock-off lever I2 into positionrto throw in the slow feed mechanical clutchthis being the position of the parts shown dotted in Figure 8, the fluid pressure entering through the passage 99 acting on the right hand annular shoulder |05 of the valve rod |06 to such a point past the spring detent I'I. As the actuating dogleav-es the valve stem A, this stem is pushed upwardly by its spring 43 (see Figure 11) allowing the pressure in the chamber 4] and its pipe connections to drain 0E the passage 50 into the drain pipe 5 I, the pressure thus being relieved on the right hand face of the feed lever engaging unit valve |06. The spring I I0 returns this valve to its neutral position shown in full lines `in Figkure 8 with the detent |0'I engaging in the annular lthe. piston |06 to its extreme right hand position shown in Figure 9. This admits pressure from the pressure line 95 through the check valve 96 and the line I|5 to the port I|6 of the valve 14a which leads through the check valve I I1 into the pilot valve at |8. This acts on the left hand face of the valve'shoulder II9 which moves the pilot valve to `the extreme right, which acts to connect the directional control valve so as to open pressure to the retire cylinder pipe 32 and discharge from the forward cylinder pipe 33 out through the passage 89 to the drain 90. This causes the .ram to retire in fast motion.

It is then neces sary to return the feed lever engaging valve |06 to neutral position as determined by the detent |01. Pressure at all times passes from the pressure line ||5 and the passage |20 through the adjustable needle valve |2 I, and is usually drained through the passage |22 to the drain pipe |23. However, when the feed knock-off moves the valve |06 to its extreme right hand position, the ball check |25 seals the drain |22, as shown in Figure 9, and pressure gradually builds up in the cylinder |26 to move the piston |06 back to the neutral position, uncovering the drain |22. After the valve |06 is moved`to this neutral position,

shutting off the supply of pressure to the line I I6, the pressure in this line bleeds off through the check valve ||'I, line I I8, and the skip station v operating valve having the valve shank B.

The ram is now retiring in fast motion. When the ram approaches its outer limit of motion, it

indexes the turret, as is well known in the art,

and just before it reaches its nal retire position, the ram element 2B strikes an abutment |30 which is provided with a stem |3| slidable through a portion of the machine frame. This abutment |30 strikes upon a collar |32 secured to the pilot valvewhich extends through a hole through the abutment |30. A spring |33 is interposed between the abutment |30 and the collar |32. The parts are so positioned, however, that the positive contact of the abutment |30 on the collar |32 serves to move the pilot valve,.together with the feed lever. and the directional control valve, to their intermediate positions, and the spring |33 there` after continues the motion of the pilot and directional control valves to their forward positions in full lines in Figure 14. This conditions the parts for the start of the cycle, including the fast forward motion of the ram and the subsequent slow feed followed by retraction at high speed, as previously described.

It might be noted that while the control valves in the casing I9 would be actuated on both directions of motion of the ram, they are ineffective to accomplish anything on the retire stroke, for the reason that in the reverse position of the pilot valve and directional control valves, the flow of fluid under pressure to accomplish the various functions done on the forward stroke is blocked. This is for the reason that, except duringI the forward positions of these valves, the grooves |35 and |36 are out of alinement with their inlet ports so that no liquid can pass, and also the groove |40 of the ldirectional control valve is out of alinement witha pair of passages |4| and |42 through the valve casing. This latter pair vof passagesV |4I and |42 form part of the hydraulic circuit controlling the carriage motions as will later appear.

Skip station cycle It may be desired to advance the ram in Yfast motion far enough to clear the turret indexing lmechanism and then retire the ram in fastV motion so as to produce an indexing action without utilizing a tool position of the turret, thus to skip oneturret position in effecting feed of the ram. Where this is desired, a dog is placed on the lay shaft at the forward desired limit'of motion of the lay shaft to depress the stem B. This supplies pressure from the pipe 45 through line |46, check valve pipe |41 to the face IIB of the pilot valve which moves the pilot Valve and the directional control valve to the extreme right hand position, thus connecting the fast motion cylinders 25 and 26 in ram reltire condition. The pressure against the face Cycle stop mechanism It is sometimes desirable to advance the ram in fast motion to a desired position whereupon the fast motion is stopped, but the -slow feed is not thrown in, and for this purpose a cycle stop valve stem C may be employed. When a dos placed on the lay shaft contacts and depresses the stem C, pressure is admitted from the line 45 to the line |50, which enters the pilot Valve at |55. In the forward position of the pilot valve, this passes through the port |56, past the ball valve |02 in behind the sleeve piston |04, which has the effect to move the pilot valve and the directional control valve to the central stop or neutral position. Pressure does not reach the feed line |0| so that the feed engaging unit is not energized and thus the fast motion is stopped without engagement of the feed. With the lever in stop position the groove |35 is out of alinement with the passage |56 so that the pressure from the stop cycle operating valve is blocked. The pressure in the chamber |58 is drained off through the pipe |60.

i in Figure 13.

Cross slide actuating' controls When it is desired to start the motion of the cross slide from its central neutral position, a dog is placed on the lay shaft to cooperate with the valve plunger D. When this valve is de` pressed, a pulse pressure is applied tolthe pipe l'|155 which passes to the directional control valve and through the groove ifi?, pipe |52, through lline check valve |63 into the feed shifter vunit 2.-`It will be noted thatv this can take place only' when the directional control valve is set Y for'ram advance, as otherwise the passage ldi would Vbe closed orf, since the valve lll would "be out of registry therewith. The ram is thus Y in condition to continuein fast motion to a pipe its and passes through the valve |70 around the port lli of the plunger il and out through the pipeV |73 to the fast motion `-`hydraulicactuator i3 whereit acts upon" piston Y'llli v/liicl'rrocks the fast motion' lever into the position for forward carriage feed where it is heldby t'he'spring detent llt. motionlever |75 is connected to a rock shaft This fast Illby the rocking of which the fast 'forward motion clutch ofthe tool slide is thrown in, that'is, the motion which brings the forward 'tool 'onthe carriage toward the work. This occurs until astop'dog 5| at Vone of the carriers 6U impingesV upon the stem E of the carriage "control valve'34.

Depression of this valve stem E applies a pressure pulse `from the pressure line i5 to the lineV |778 which passes the T coun-ling |79 through the pipe |35, through the T coupling |86, thepipe lill, the 'checl'valve theipipe v|89 and double check valve ld to the fastin tion actuator 13 at thefport lei (seeigure l2).

The pressure here acts upon a pair .oflpistons |92, which acting through the pluri-gers is,

' moves the piston |74 and the reverse carriage Vout in this neutral vposition by the detent |76.

The pressure impulse produced by =depressionfof YtheV valve stem E also 'passesfrom the T fitting ilQby pipe |80, check valve |8| 'to the carriage feed lever knock-off lh. Thiscarriage lever 'knock-off is identical' with fthe ram knock-off 'valve, the pressure acting to force the piston in thedirection as `heretofore described in convne'ction with' theV ram-knock-oi-ftofset the carriage knockeoff vto slow feedpositi'cn. Also from the T 'iSSfpressure is applied through fthe pipe llltothe -p'assage'il'l of the feed shifter unit "l2 (Figure 13),Athrowing theplunger |12 to the fright, rocking the rocker illl'whi'ch controls-the forwardY and-back" fee-d clutch iorfthe'o'arriage feed motion, this closing-'the pressure port l'll from the pipe |i'3 land-'the plungerl |72 and opening from the pressurep'ort lll) through the plunger portil' to'the pipe 29|. vlhis'condiM tions the feed shifter unit so: that atj its next actuationv the carriage is reversed infdirection at feeding speed. l

Pressure enters it through the f The carriage now proceedsin slow mechanical feed until the carriage knock-olf spool 2|l5*is l moved rearwardly by impin'gement thereon of the abutment 296, this as more fully shown'and'described in the Lovely Patent No. 2,006,144, resulting in the release of the carriage knock-off. 'Ihe release of this knockfoif throws out the slow-feed clutch and moves the knock-off valve tothe extremeouter position, Vheretofore describedin cona nection with the ram knock-off, whichadmits a pressure rimpulse to the lpipe 2H). `This impulse passes through the check -valve |63,"into the'pipe i of they feed control unit 12, thepre'ssure'passage |10, and? out throughthe pipe 20| Vwhich leads to the right hand' plunger |94'of thecarriage fast motion mechanism, and -throwsthe lever |75 in clockwise direction to throw liii-.the high speed reverse carriage clutch. The return fast' motion continues until the cross slide centered, as determined by the depression by a-'cenf ter stop dog 6| of the valve'stem F, whichr'admits a pressure impulse to the pipe 2|2, check valve 2|3, line Zie, check valve IBS, line |89, the double check valve |93, and the pipe |9| to thecarriage fast motion. mechanism in position to shift the carriage fast motion ro'ck'shaft I ll to neutral position as previously described, so that thev cross l slide stops with the valve plunger F depressed.

This completes one-half of the automatic cycle for the cross slide. This means that a Vccmtinuous pressure will be applied lon 'both pistons VI'Ili and |94 through pressure applied to the pistons l?. It will be noted that the'pistons |14 and |94 are larger than the pistons |92 since it is necessary that the pulse pressure applied'to either piston I'M or |913 overcome the pressure'against .pistons |92 to move the fast motion lever for desired fast motion.

. The second half of the cycle causes the back tool to move forwardly, first in fast motion'and then in slow motion,v and then to be retracted'in Vanother dog 6| on the carriage which contacts and depresses the valve stemG just'before en gagement of the center stop dog with itsoperative valve stem F. This produces a pressure pulse into the pipe 222 leading to the outer Yend of the direction control valve (see Figure 14), which forces `this directional control valve to the left to its ram advanced position, throwing the operating handle |35 tothe full line position shown, this valve having previously beenleft in the central stop or neutral position where it was held by the detent 9|. This causes the ram to advance until another stop dog I8 on Ythe lay shaft depresses the valve stem D, supplyingl a pressure pulse to ythe pressure pipe |65 through the directional control valve |40, to the pipe |62 as previously described, this acting through the e check valve |63 and the pipe |64 to reach the feed shifterunit which is now, in such position, as previously described, that the fluid is delivered through the pipe 29|, lcontinuing the rreturn in fast motion of the carriage until .the return'stop dog on the cross sli-de depresses the valve'st'em H. Depression of the valve stem Hsupplies a pressure impulse to the Apipe25 whichfpasses through the T1225, the line 23s, im@ Cheek valve 2|3, line 2|4, line check valve |88, doulole check valve |98 and fast motion leverY operating mechanisrn, asV previously described, to causefthev pistons |92 to move'the fast motion lever |15 to neutral position while -at -the same ltime the-'fluid pulse in the T 226 passes through line 221, T 228, line 231, feed shifter unit l2 to force the plunger 229 to the right, rocking the feed shifter lever into the position shown in Figure 13. This shif-ts the gears to give a back feed direction. The carriage is now feeding in return direction and when the abutment 235 (Figure 5) strikes the feed knock-ofi spool 265, the slow feed is thrown out as previously described and the movement of the cross slide is reversed to a fast motion forward to continue to the center neutral point where it stops, depressing the valve stem F.

Referring to Figure 13, it will be noted that the pressure is drained from each of the passages 260 and il! when they are out of operative position through the drain passage 231 and drain pipe 233.

It is sometimes desirable to provide a time delay at the end of .the feed and before the commencing of the retire fast m-otion of the ram or of the cross slide. This may be easily attained by well known mechanism, and as shown herein for this purpose, dash pots, indicated somewhat diagrammatically at Zilli and 21H on Figure 22, have been provided. This time delay is of advantage in removing the spring from the cutting tools so that the tools cut to their maximum depth before being retired. The particular slow speed mechanism has not been indicated herein since it is already old and well known in the art, and commonly provision will be made for selecting any of a considerable variety of speeds, depending upon the particular requirements of the operation to be performed, this also being well kno-wn in the art.

From the foregoing description of an embodiment of this invention, it should be evident to those skilled in the art ythat various changes and modifications might be made without departing from the spirit or scope of the invention.

I claim:

l. In a machine tool having a work support and a tool support, mechanically actuated means for moving one of said supports toward the other of said supports in slowfeed, and means for releasing said slow feed when said movable support reaches a predetermined feed position, a source of hydraulic pressure, hydraulic fast motion mechanism for moving said movable support in fast motion advance and retire, means actuated by said movable support when said movable support reaches a predeterminedposition in its advance motion for producing a pressure impulse from said source, means actuated by said pressure impulse to throw out the fast motion advance hydraulic mechanism and to throw in said slow motion mechanically actuated feed, means actuated by said slow motion feed release means for producing a second pressure impulse from said source, and means actuated by said second pressure impulse to throw in said hydraulic fast motion mechanism to retire said movable support in fast motion.

2. In a turret lathe having a headstock provided with a rotary work holding spindle, a ram movable toward and from said spindle, an indexing tool holding turret carried by said ram, mechanically actuated means for moving said ram toward said headstock in slow feed, and means for releasing said slow feed when said ram reaches a predetermined feed position, a source of hydraulic pressure, hydraulic fast motion mechanism for moving said ram in fast motion advance and retire with reference to said headstock, means actuated by said ram when said ram reaches a predetermined position in its advance motion for producing a pressure impulse from said source, means actuated by said pressure impulse to throw out the fast motion advance hydraulic mechanism and to throw in said slow motion mechanicaliy actuated iced means, means actuated by said slow motion feed release means for producing a second pressure impulse from said source, and means actuated by such second pressure impulse to throw in said hydraulic fast motion mechanism to retire said ram.

8.1n a lathe, a headstock, a tool carrier movabie toward and from work carried said hea-:lfstock, hydraulic mechanism for moving said carrier Vin fast motion toward and from .said headstock, a movable valve mechanism for determining the direction of motion of said hydraulic moving mechanism, a mechanical slow feed mechanism for moving said carrier toward said headstoek, a knock-off for throwing out said slow feed mechanism when said carriage reaches a predetermined feed point relative to said headstock, mechanism actuated by said carrier as it is moved hydraulically toward said headstock and reaches a predetermined point to throw out said hydraulic mechanism and to throw in said slow feed mechanism, means actuated by said iin cir-off when it throws out said slow feed to condition said valve mechanism for fast hydraulic return of said carrier, and means actuated by said carrier when it reaches a predetermined retire position to throw out said hydraulic mechanism.

4. In a lathe having a headstock, a rotary work carriage spindle journaled in said headstock, a movable to advance and retire relative to said headstock, a source of hydraulic pressure, and a tool carrier turret carried by said ram, hydraulic means for moving said ram in fast motion, an axially movable valve controlling the direction of motion of said rain in fast motion and having end positions opening pressure from said source to move said ram in one direction while discharging pressure previously effective to move said ram in the opposite direction and an intermediate neutral position cutting ofi all iiuid pressure effects to move said ram, means actuable by said ram at its retire limit of motion for moving said valve to ram-advance position, mechanical means for advancing said ram in slow feed toward said headstock, hydraulic means actuated by said ram at a predetermined position to throw out said hydraulic advance fast motion and throw in said slow mechanical feed, and means actuated by said ram at a predetermined feed limit to throw out said slow feed and throw in said hydraulic fast motion in retire direction.

RALPH M. GAMBLE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

